Diaphragm support

ABSTRACT

A speaker comprising rear support means having threads provided at the rear part of a diaphragm, a ring weight tied at each end of said threads and arranged in space around said diaphragm, and fulcrums mounted on a yoke to support said threads. Front support means are also disclosed. This structure keeps the diaphragm in balance and permits reduction of stiffness and improvement of the frequency characteristics of the speaker.

United States Patent 1191 UNITED STATES PATENTS l/1927 Harrison 181/32 A Tnrnga Apr. 16, 1974 [54] DIAPHRAGM SUPPORT FOREIGN PATENTS OR APPLKIATIONS lnventori Tomi) g Daini, Shiotaso, 320,647 10/1929 Great Britain 179/1155 R 7-6440 Tsudanuma, Narashino-shi, 'ghlhglke-pllanglw Primary Examiner-Kathleen H. Clafi'y Filed2 g- 1972 Assistant Examiner--Thomas L. Kundert [21] Appl No: 279,913 Attorney, Agent, or Firml.awrence I. Field [30] Foreign Application Priority Data ABSTRACT Sept. 7, Japan speaker comprising rear upport means having Sept. 7, 1971 Japan 46-81124 threads provided at the rear part f a diaphragm a ring weight tied at each end of said threads and ar- [52] US. Cl. 179/1155 R, 181/32 R ranged i Space around i diaphragm and fulcrums [51] lint. Cl H04r 9/06 mounted on a yoke to support said threads Front Field of Search 179/1 R1 1 port means are also disclosed. This structure keeps the 179/1 E, 1155 E 181/32 R, 32 A diaphragm in balance and permits reduction of stiffness and improvement of the frequency characteristics [56] References Cited f the Speaker 3 Claims, 5 Drawing Figures PATENTEDAPR 16 l974 v 3 80d 994 saw 1 [IF 2 DIAPHRAGM SUPPORT The present invention relates to a speaker, particularly to a speaker which is improved in the means which supports the rear part adjacent to the voice-coil of a diaphragm and/or the front part of a diaphragm.

It is necessary to lower the resonance frequency in the low region in order to have high efficiency of a speaker in regeneration of low frequency, therefore a diaphragm of a speaker must be supported as loosely as possible, thereby to reduce stiffness. However, if the diaphragm is supported too loosely, it permits a swaying motion and warping, or after many years it may slip down from the correct point in a gap of magnetic circuit, causing a voice-coil of the diaphragm to make contact with the magnet in the magnetic circuit thereby producing an abnormal tone; The supporter keeping the rear part of the diaphragm centered around the voice-coil generally used is a damper of concentric circular wave shape made of. cloth containing resin, and it has excellent linearity and is dust-proof, however, the area to bond with the diaphragm is too big, therefore the damper itself causes abnormal tone, or there are caused mountains and valleys in frequency characteristics owing to reflected waves or the like by a damper, thereby causing the tone qualityto grow worse. Also, since it is stiffened by containing resin to maintain its form, stiffness may not be reduced too much.

Further, the support around the front part in the speaker diaphragm functions as helping the diaphragm to vibrate correctly and therefore exerts influences upon the distortion characteristics and the low frequency characteristics, which heretofore have had a bad effect by reflected waves or the like from the sup port around front part of the diaphragm, especially there are caused mountains and valleys easily in the characteristics in a medium frequency region. Also, if the diaphragm is supported rigidly, resonance frequency in the low region becomes high and efficiency in regeneration of the low frequency becomes low, therefore free edge is used to have high flexibility and the-edge is made of deerskin or the like which is very flexible and is excellent for inner dissipation. Consequently the diaphragm must be supported loosely and stiffness must be reduced. However, if the diaphragm is supported too loosely, it brings about a swing motion to warp, or after many years, it may slip down from the correct point to cause abnormal tone.

As a way to get rid of said defects, there is a known method to support by thread hanging. However, in that method only by precisely regulating strain of the thread can the diaphragm be supported in the correct point in a gap of the magnetic circuit. Furthermore it is influenced by temperature and humidity, also it may not be possible to avoid slackness of thread from year to year. Also, if thread is too loose, it becomes unstable, so it is necessary to draw thread strongly to some extent, therefore stiffness may not be reduced. These are the defects of said method.

The present invention avoids said defects. It is an object of the present invention to provide an improved speaker support means which may keep the diaphragm, that is the voice-coil of the diaphragm in the correct point in a gap of the magnetic circuit by electromagnetic power of voice-coil when the speaker is used, by hanging rear part of the diaphragm near the voice-coil in a balanced condition or by hanging front part of the diaphragm by means of a fulcrum ring through threads, keeping balance by means of springs.

It is another object of the present invention to provide an improved speaker of which resonance frequency in the low region is lowered by reducing stiffness, whereby the frequency characteristics are improved preferably.

According to the present invention, there is provided a speaker comprising a rear support means having some threads provided near voice-coil at the rear part of a diaphragm, a ring connected to each end of said threads and disposed in space around said diaphragm, and some fulcrums mounted outside of yoke of the speaker to support said threads, and/or a front support means having some threads one end of which is fixed around the front part of the diaphragm and to whose other ends springs are fixed, a ring secured on the yoke of the speaker to secure each end of said springs, a fulcrum ring which is connected to said ring in a concentric way to support said threads and is consequently secured to said yoke.

In a speaker provided with the rear support means of the present invention, when voice-coil is kept in the correct position in a gap of the magnetic circuit, the po sition of the voice-coil is not changed as long as that balance is kept. However, after many years, that balance may be changed, or the position of the voice-coil may be changed by external force. Even if these changes may occur, the voice-coil actually moves to the center in the gap of the magnetic circuit, that is, it may adjust itself when it is constructed according to the present invention. Accordingly, there is no trouble for utilizing this speaker in spite of changes after many years. Therefore, when the rear support means of this invention is utilized, it is not necessary to closely control strain of the thread as in the past. Also since it is not necessary to draw thread tightly, stiffness may be reduced. Further since the voice-coil is kept in a condition in which the voice-coil may be moved by a little force, it always vibrates at the safest position by the action of electro-magnetic force. Accordingly vibration of the diaphragm is not restrained so that good quality of tone with very little distortion may be obtained and the lowest resonance frequency may be sufficiently lowered and also transient characteristics may be distinguished.

Also when the front support means of this invention is applied at the front part of the diaphragm, and when threads become slack for any reason, standstill frictional force becomes weak, so thread moves and works as balancing in tension of springs and threads hanging the diaphragm by displacement of the threads whereby the threads in each direction may be drawn by the springs with substantially equal strength. Also if the threads are drawn strongly for any reason, standstill frictional force becomes strong, so that the threads do not move and balance may be kept. Therefore the supporting position near the diaphragm does not change in the lateral direction. Thus since the part around the diaphragm is hung through the threads, free edge is not necessary to support the diaphragm, so it is able to be very soft. Also it is possible to be perfectly free. If said thread hanging is fitted with proper strain of the springs and proper frictional force of the fulcrum ring, it always keeps in balance, and it does not go out of balance even after many years. Stiffness of edges may be reduced, vibration of the diaphragm is not restrained,

whereby good quality of tone with little distortion may be obtained.

The above and other objects and features of the present invention will become more apparent upon reading the following detailed specification with reference to the accompanying drawings which show preferred form of embodiments of the present invention and in which:

FIG. 1 is a sectional view which shows the first preferred form of embodiment of the speaker according to the present invention;

FIG. 2 is afragmental perspective view of the speaker shown in FIG. 1;

FIG. 3 is a sectional view which shows the second preferred form of embodiment of the speaker according to the present invention;

FIG. 4 is a'front view of the speaker shown in FIG. 3;

FIG. 5 is a sectional view which shows the third preferred form of embodiment of the speaker according to the present invention;

Referring to FIGS. 1 and 2 which show the first embodiment of the speaker according to the present invention, reference number 1 is a diaphragm, around the central rear part la whereof voice-coil 2 is adhered. Near the voice-coil of the diaphragm some threads 3 secured, the rear part of the diaphragm l is hung by a ring weight 5 which is kept in balance by some fulcrums 4 provided respectively on supporting studs 9a fixed around yoke 9 through the threads 3. The diaphragm is inserted into a gap 6 of magnetic circuit formed by a magnetic pole 10. The threads 3, the fulcrums 4, the ring weight 5 form the rear support means A as a whole. Therefore since the voice-coil 2 may be moved freely in any direction by a little force, the voice-coil 2 may be supported at any position in the gap of the magnetic circuit. The size of the fulcrums is chosen so that the threads 3 do not touch to the ring weight 5 during axial vibration of the diaphragm I. The fulcrums are preferably shaped as rollers and are provided with bezel on the circumference thereof to support threads 3. It will of course be understood that the fulcrums may be fixed or rotatably supported on the supporting studs 9a respectively. According to the illustrated form of this embodiment, four threads 3 and four fulcrums 4 are used, whereby the diaphragm is supported in four directions, however it will of course be understood that it may be in three or five directions or more. The front part 7 of the diaphragm 1 is adhered on the yoke 9 through free edge 8 in the usual way.

Referring to FIGS. 3 and 4 which show the second preferred form of the speaker according to the present invention, reference number 1 is a diaphragm as shown in said first embodiment, at its central rear part la a voice-coil 2 is adhered. Also the voice coil 2 is supported by usual damper and inserted into a gap of magnetic circuit. The front part 7 of the diaphragm l is adhered to yoke 9 through free edge 8. The front support means B is provided so as to support the front part of the diaphragm l, and is mainly formed by threads 14, springs 11, supporting rods 13, a medium ring 12 and a fulcrum ring 15. One end of the threads 14 is connected to the circumferential part 7 of the diaphragm l and the threads are passed through the fulcrum ring 15 of the supporting rod 13 and also are connected with each spring 11 connected to the medium ring 12 secured on the supporting rod 13 at the other end.

Namely, the front part 7 of the diaphragm l is hung on the fulcrum ring 15 through the threads 14 drawn by the springs 11 so as to support the diaphragm. The strength of the springs 11 connected with the threads 14 is chosen so that the diaphragm 1 does not deform, and it is sufficient that the standstill frictional force working between the threads 14 and the supporting ring 15 may support the weight of the diaphragm 1. It is preferred that four threads 14 and four fulcrums 11 are used, so the diaphragm is supported in four directions. Also since the part 7 of the diaphragm l is hung by means of the threads as described above, the free edge 8 is not necessary to support the diaphragm I, therefore the part which is supported by yoke 9 may be formed very pliantly, also it is possible for edge 8 to be perfectly free. Although the front support means B is secured to the yoke 9 by means of the supporting rods 13 as illustrated, the means B may be secured to a stud (not illustrated) mounted on the magnetic pole.

FIG. 5 is a sectional view which shows the third form of the speaker according to the present invention. This embodiment is a form added the front support means B applied in the second embodiment to the rear support means A applied in the first embodiment and this construction may contain all the effects which come from said first and second preferred forms of embodiments. Namely the rear part 1a of the diaphragm I near the voice-coil 2 is kept balanced by the rear support means A comprising the threads 3, the fulcrums 4, and the weight 5. Further the front part 7 of the diaphragm l is kept in balance by the front support means B namely the threads 14, the springs 11, the supporting rods 13, the medium ring 12 and the fulcrum ring 15. While the present invention has been illustrated and described with particular reference to specific embodiments shown in the accompanying drawings, it will be understood that the same is merely exemplary and not restrictive and therefore many variations can be made without departing from the spirit and scope of the present invention, and all of these variations are to be embraced within confines of the claims that follow.

What is claimed is:

1. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising:

a plurality of individual threads each connected to the rear part of said diaphragm, near said voice coil;

an annular weight encircling said diaphragm but spatially separated from said diaphragm, said weight being connected to the opposite end of each of said threads and being axially spaced forwardly from the portion of each thread which is connected to the rear part of said diaphragm;

a yoke on said speaker;

means on said yoke to provide support for each of said threads between the ends thereof, whereby the rear end of said speaker is supported in a manner which permits it to move freely both axially and radially;

and means securing the front edge of said diaphragm to said yoke.

2. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising:

a yoke on said speaker;

a plurality of individual threads each having one end fixed on the front part of said diaphragm and each thread having its other end connected to one end of a spring;

a supporting medium ring connected to the yoke of the speaker and connected to the other end of each of said springs;

a fulcrum ring provided concentrically to said medium ring and fixed to said yoke, each of said threads passing through said fulcrum ring between the ends of said threads;

and supporting rods mounted on said yoke, and connected to each of said supporting medium ring and said fulcrum ring where the front end of said speaker is supported in a manner which permits it to remain in balance.

3. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising:

rear support means to suspend the rear part of said diaphragm in balance near said voice coil; and

front support means to support the front part of said diaphragm;

wherein said rear support means includes a plurality of individual threads each connected to the rear part of said diaphragm, near said voice coil;

an annular weight encircling said diaphragm but spatially separated from said diaphragm, said weight being connected to the opposite end of each of said threads and being axially spaced forwardly from the portion of each thread which is connected to the rear part of said diaphragm;

a yoke on said speaker;

means on said yoke to provide support for each of said threads between the ends thereof, whereby the rear end of said speaker is supported in a manner which permits it to move freely both axially and radially;

and means securing the front edge of said diaphragm to said yoke;

and said front support means includes:

a plurality of individual threads each having one end fixed on the front part of said diaphragm and each thread having its other end connected to one end of a spring;

a supporting medium ring connected to the yoke of the speaker and connected to the other end of each of said springs;

a fulcrum ring provided concentrically to said medium ring and fixed to said yoke, each of said threads passing through said fulcrum ring between the ends of said threads;

and supporting rods mounted on said yoke, and connected to each of said supporting medium ring and said fulcrum ring where the front end of said speaker is supported in a manner which permits it to remain in balance. 

1. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising: a plurality of individual threads each connected to the rear part of said diaphragm, near said voice coil; an annular weight encircling said diaphragm but spatially separated from said diaphragm, said weight being connected to the opposite end of each of said threads and being axially spaced forwardly from the portion of each thread which is connected to the rear part of said diaphragm; a yoke on said speaker; means on said yoke to provide support for each of said threads between the ends thereof, whereby the rear end of said speaker is supported in a manner which permits it to move freely both axially and radially; and means securing the front edge of said diaphragm to said yoke.
 2. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising: a yoke on said speaker; a plurality of individual threads each having one end fixed on the front part of said diaphragm and each thread having its other end connected to one end of a spring; a supporting medium ring connected to the yoke of the speaker and connected to the other end of each of said springs; a fulcrum ring provided concentrically to said medium ring and fixed to said yoke, each of said threads passing through said fulcrum ring between the ends of said threads; and supporting rods mounted on said yoke, and connected to each of said supporting medium ring and said fulcrum ring where the front end of said speaker is supported in a manner which permits it to remain in balance.
 3. In a speaker which includes a diaphragm and a voice coil secured adjacent to one end of said diaphragm, the improved means for supporting said diaphragm in balance in the proper position in a gap of the magnetic circuit which includes said voice coil, comprising: rear support means to suspend the rear part of said diaphragm in balance near said voice coil; and front support means to support the front part of said diaphragm; wherein said rear support means includes a plurality of individual threads each connected to the rear part Of said diaphragm, near said voice coil; an annular weight encircling said diaphragm but spatially separated from said diaphragm, said weight being connected to the opposite end of each of said threads and being axially spaced forwardly from the portion of each thread which is connected to the rear part of said diaphragm; a yoke on said speaker; means on said yoke to provide support for each of said threads between the ends thereof, whereby the rear end of said speaker is supported in a manner which permits it to move freely both axially and radially; and means securing the front edge of said diaphragm to said yoke; and said front support means includes: a plurality of individual threads each having one end fixed on the front part of said diaphragm and each thread having its other end connected to one end of a spring; a supporting medium ring connected to the yoke of the speaker and connected to the other end of each of said springs; a fulcrum ring provided concentrically to said medium ring and fixed to said yoke, each of said threads passing through said fulcrum ring between the ends of said threads; and supporting rods mounted on said yoke, and connected to each of said supporting medium ring and said fulcrum ring where the front end of said speaker is supported in a manner which permits it to remain in balance. 